Field of the Invention
The present invention relates to a directed self-assembling composition for pattern formation, and a pattern-forming method.
Discussion of the Background
Miniaturization of various types of electronic device structures such as semiconductor devices and liquid crystal devices has been accompanied by demands for miniaturization of patterns in lithography processes. At present, although fine resist patterns having a line width of about 90 nm can be formed using, for example, an ArF excimer laser light, further finer pattern formation is required.
To meet the demands described above, some pattern-forming methods in which a phase separation structure by directed self-assembling, as generally referred to, is utilized that spontaneously forms an ordered pattern have been proposed. For example, an ultrafine pattern-forming method by directed self-assembling has been known in which a block copolymer is used which is obtained by copolymerizing a monomer compound having one property with a monomer compound having a property that is distinct from the one property (see Japanese Unexamined Patent Application, Publication No. 2008-149447, Japanese Unexamined Patent Application (Translation of PCT Application), Publication No. 2002-519728, and Japanese Unexamined Patent Application, Publication No. 2003-218383). According to this method, annealing of a composition containing the block copolymer results in a tendency of clustering of polymer structures having the same property, and thus a pattern can be formed in a self-aligning manner. In addition, a method of forming a fine pattern by permitting directed self-assembling of a composition that contains a plurality of polymers having properties that are different from one another has been also known (see US Patent Application, Publication No. 2009/0214823, and Japanese Unexamined Patent Application, Publication No. 2010-58403).